Energy detection spectrum sensing of M-ary QAM systems over AWGN channels

This article addresses energy detection for spectrum sensing of M-ary quadrature amplitude modulation (QAM) systems. Analytical expressions are developed for the average probability of detection in these systems. The analytical results are validated by numerical simulations and comparisons with different approximated approaches found in the literature are made. We see that the approximations usually found in existing literature are good for a large number of sensing samples or for very low SNR levels, but, otherwise, the use of a particular modulation scheme may have an impact on sensing performance.